Assume that the water temperature is 10 oC and the settling tank has a 3-m depth. Calculate the theoretical settling velocity (m/s), overflow rate(m3/m2-d), and hydraulic detention time (h) required in the following cases. a. Calcium carbonate precipitates with a specific gravityof 1.2 and diameter of 0.1 mm. (These particles will be removed in a settler after precipitative softening, which is a process we will discuss later in the course.)b. Alum floc with a specific gravity of 1.002 and diameter of 1.0mm. (These particles are to be removed in a settling tankafter coagulation/flocculation, which are processes that we will discuss later in the course.)c. What will be the corresponding design loading rate and detention time for the above cases if the efficiency of the settling basins is 50%, assuming the removal is linearly related to efficiency?

Ahe-xe mixture containing a 0.75 mole fraction of helium is used for cooling electronics in an avionics application. at a temperature of 300 k and atmospheric pressure, calculate the mass fraction of helium and the mass density, molar concentration and molecular weight of the mixture. if the cooling capacity is 10 l, what is the mass of the coolant?

A3-mm-thick panel of aluminum alloy (k 177 w/m-k, c 875 j/kg-k and ? = 2770 kg/m) is finished on both sides with an epoxy coating that must be cured at or above t,-150°c for at least 5 min. the production line for the curing operation involves two steps: (1) heating in a large oven with air at ts,0-175°c and a convection coefficient of h, 40 w/m2. k, and (2) cooling in a large chamber with air at 25°c and a con- vection coefficient of he 10 w/m2.k. the heating portion of the process is conducted over a time interval te which exceeds the ime required to reach 150°c by 5 min (h = r + 300 s). the coating has an emissivity of ? = 0.8, and the temperatures of the oven and chamber walls are 175 and 25°c, respectively. if the panel is placed in the oven at an initial temperature of 25°c and removed from the chamber at a safe-to-touch tempera ture of 37°c, what is the total elapsed time for the two-step curing operation?

Water vapor initially at 10 bar and 400 °c is contained within a piston-cylinder assembly. the water lost heat to the surrounding according to isochoric (iso-volumetric) process until its temperature is 150 °c. the water is then condensed isothermally to saturated liquid. for the water as a system, calculate the work in kj/kg